Hypertension is a condition from which many people suffer. It describes a constant state of elevated blood pressure which can be caused by a number of factors, for example, genetics, obesity or diet. Baroreceptors located in the walls of blood vessels act to regulate blood pressure. They do so by sending information to the central nervous system (CNS) regarding the extent to which the blood vessel walls are stretched by the pressure of the blood flowing therethrough. In response to these signals, the CNS adjusts certain parameters so as to maintain a stable blood pressure.
US Patent Application Publication 2003/0060858 to Kieval et al., which is incorporated herein by reference, describes devices, systems and methods by which the blood pressure, nervous system activity, and neurohormonal activity may be selectively and controllably reduced by activating baroreceptors. A baroreceptor activation device is positioned near a baroreceptor, for example a baroreceptor in the carotid sinus. A control system may be used to modulate the baroreceptor activation device. The control system may utilize an algorithm defining a stimulus regimen which promotes long term efficacy and reduces power requirements/consumption.
US Patent Application Publication 2005/0154418 to Kieval et al., which is incorporated herein by reference, describes systems and methods to provide baroreflex activation to treat or reduce pain and/or to cause or enhance sedation or sleep. Methods involve activating the baroreflex system to provide pain reduction, sedation, improved sleep or some combination thereof. Systems include at least one baroreflex activation device, at least one sensor for sensing physiological activity of the patient, and a processor coupled with the baroreflex activation device(s) and the sensor(s) for processing sensed data received from the sensor and for activating the baroreflex activation device. In some embodiments, the system is described as being fully implantable within a patient, such as in an intravascular, extravascular or intramural location.
US Patent Application Publication 2006/0074453 to Kieval et al., which is incorporated herein by reference, describes a method for treating heart failure in a patient which involves activating a baroreflex system of the patient with at least one baroreflex activation device and resynchronizing the patient's heart with a cardiac resynchronization device. Activating the baroreflex system and resynchronizing the heart may be performed simultaneously or sequentially, in various embodiments. In some embodiments, one or more patient conditions are sensed and such condition(s) may be used for setting and/or modifying the baroreflex activation and/or heart resynchronization. A device for treating heart failure includes a baroreflex activation member coupled with a cardiac resynchronization member. Some embodiments further include one or more sensors and a processor. In some embodiments, the device is fully implantable.
US Patent Application Publication 2005/0027346 to Arkusz et al., which is incorporated herein by reference, describes a tubular vascular stent graft with a passively pulsating midsection where the difference between the cross-sectional areas of the lumen under the systolic and diastolic pressures after the implantation is 10% or more. The pulsating stent graft accumulates blood during the systolic pressure wave thus lowering the peak value of the tugging force at the proximal attachment site.
PCT Publication WO 03/076008 to Shalev, which is incorporated herein by reference, describes an implantable device which uses the carotid baroreflex in order to control systemic blood pressure. The implant includes sampling and pulse stimulation electrodes preferably located on the carotid sinus nerve branch of the glossopharyngeal nerve, adjacent and distal to the carotid sinus baroreceptors. The stimulators have an external control unit, which communicates with the implant for determining appropriate operational parameters, and for retrieving telemetry information from the device's data bank. Typically, two internal devices are implanted, one at each side of the patient's neck.
PCT Publication WO 04/073484 to Gross et al., which is incorporated herein by reference, describes apparatus which includes an inflatable bladder, adapted to be coupled to a blood vessel of a subject carrying oxygenated blood, such that an interior of the bladder is in fluid communication with the blood. The apparatus also includes a piston in mechanical communication with the bladder; a motor, adapted to synchronize contraction and expansion of the bladder with a cardiac cycle of the subject by applying a motor force to the piston; and a spring, adapted to apply a spring force to the piston. In some embodiments of the invention, a counterpulsation system comprises one or more springs, which are adapted to be inserted into an artery of a subject, such as a descending aorta. Typically, each of the springs is planar, i.e., flat rather than helical, and has a generally sinusoidal shape. For applications comprising more than one spring, the plurality of springs are arranged in substantially a single plane. The counterpulsation system causes the artery to have a cross-sectional area during diastole that is less than the cross-sectional area would be during diastole without use of the counterpulsation system. For example, the counterpulsation system may cause the artery to have a cross-sectional shape during diastole that generally resembles an ellipse. Use of the counterpulsation system is described as thus typically increasing diastolic blood pressure and decreasing systolic blood pressure, thereby providing counterpulsation treatment to the circulation of the subject.
CVRx (Minneapolis, Minn.) manufactures the CVRx® Rheos Baroreflex Hypertension Therapy System, an implantable medical device for treating patients with high blood pressure. The product, which is under clinical investigation, works by electrically activating the baroreceptors, the sensors that regulate blood pressure. These baroreceptors are located on the carotid artery and in the carotid sinus. CVRx states that when the baroreceptors are activated by the Rheos System, signals are sent to the central nervous system and interpreted as a rise in blood pressure. The brain works to counteract this perceived rise in blood pressure by sending signals to other parts of the body to reduce blood pressure, including the heart, kidneys and blood vessels.
The following patents and patent applications, which are incorporated herein by reference, may be of interest:
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